Ethernet has characteristics of high data transfer rate and high adaptability. Also, the establishment of Ethernet can boost domestic economy and enable ISPs (Internet Service Providers) to integrate network technology. In terms of cost and technology, the conventional ATM (Asynchronous Transfer Mode) is complicated and high in cost. Thus, its market share is lowered significantly. Fortunately, Gigabit Ethernet is emerging as complimentary means. Gigabit Ethernet has a transfer distance up to 150 km. Also, Gigabit Ethernet can be combined with fiber optics for extending its application to LAN (local area network) and MAN (metropolitan area network).
Moreover, advantages including flexible bandwidth management, reduced complication of the Internet, supporting wideband service of high capacity, and provision of diversified, substantial, and high value-added telecommunication services to ISPs and companies are made possible by Ethernet. Thus, as viewed by companies, Ethernet, as a novel, advanced network, has benefits of being simple, low cost, powerful, and high bandwidth. Also, Ethernet can lift the limitation caused by complicated, fixed infrastructure and WAN (wide area network) connection. As viewed by ISPs, the high bandwidth of Ethernet can provide more value-added services to end users, resulting in an increase of service quality.
Gigabit Ethernet, also called 1000Base-T, is a branch of Ethernet. The difference between Gigabit Ethernet and Ethernet is that the former has a data transfer rate of 1,000 Megabits, i.e., 10 times of 100Base-T. A standard Gigabit Ethernet called IEEE802.3z was published in 1998. But 1000Base-T standard (i.e., Gigabit Ethernet complied with IEEE 802.3 using category 5 (CAT-5) copper wire) was formally approved in 1999. Such standard makes Gigabit Ethernet available other than server room and trunk room. Hopefully, Gigabit Ethernet will be as popular as 10/100 Ethernet in a near future. 802.3z Gigabit Ethernet operates well, has a speed of 10 times as that of 100Base-T, and is capable of operating in various environments. Further, 1000Base-T has a rearward adaptability and is adapted to cooperate with 10/100 Ethernet. Furthermore, 1000Base-T uses CAT-5 wire or even higher.
A prior connection of an Ethernet switch 3 and a GBIC (Gigabit Interface Converter) module 4 is shown in FIG. 1. As shown, the Ethernet switch 3 comprises a GBIC interface connector (GBIC I/F) 31 coupled to the GBIC module 4 so that the Ethernet switch 3 is able to provide one of two operating voltages (specifically, DC voltages in the following description) to the GBIC module 4 via the GBIC I/F 31 as detailed below.
(1) The Ethernet switch 3 is able to provide 5V voltage to the GBIC module 4 in a first case in which 5V voltage is fed to a GBIC logic circuit 41 and 5V voltage is used by the GBIC module 4. Alternatively, a GBIC power circuit 42 is responsible for lowering 5V voltage as 3.3 V, 2.5V, or 1.8V voltage prior to feeding to the GBIC logic circuit 41 and being used by the GBIC module 4.
(2) The Ethernet switch 3 is able to provide 3.3V voltage to the GBIC module 4 in a second case in which 3.3V voltage is fed to the GBIC logic circuit 41 and 3.3V voltage is used by the GBIC module 4. Alternatively, the GBIC power circuit 42 is responsible for lowering 3.3V voltage as 2.5V or 1.8V voltage prior to feeding to the GBIC logic circuit 41 and being used by the GBIC module 4.
In view of the above, a user has to check voltage at the GBIC I/F 31 in order to confirm whether the voltage is the one required by the GBIC module 4 prior to connecting the GBIC module 4 and the Ethernet switch 3 together at the GBIC I/F 31. Otherwise, two undesired conditions may occur.
(1) The output voltage of the GBIC module 4 will be less than the input voltage thereof when the GBIC module 4 is used to step down voltage. For example, voltage applied to the GBIC logic circuit 41 will be too low if the input voltage of the GBIC module 4 measured at the GBIC I/F 31 is 3.3 V.
(2) Voltage applied to the GBIC logic circuit 41 is 5V as measured at the GBIC I/F 31 while the operating voltage of the GBIC module 4 is 3.3 V. As an end, the GBIC logic circuit 41 will be damaged due to too much current.
Thus, it is desirable among consumers and Ethernet switch 3 manufacturers to provide means for adapting a GBIC module 4 to an Ethernet switch 3 capable of outputting different voltages when the GBIC module 4 is coupled to the Ethernet switch 3 in order to overcome the above drawbacks (e.g., voltage of the GBIC logic circuit 41 being too low or the GBIC logic circuit 41 being damaged) of the prior art.